ACC/AHA/ESC/WHF Universal Definition of Myocardial Infarction Classification System and the Risk of Cardiovascular Death: Observations From the TRITON-TIMI 38 Trial

Study Questions:

What is the prognostic implication of the subtypes of myocardial infarction (MI), as defined by the universal definition of MI?

Methods:

The authors retrospectively evaluated the association between new or recurrent MI by subtype according to the American College of Cardiology/American Heart Association/European Society of Cardiology/World Heart Federation (ACC/AHA/ESC/WHF) Task Force for the Redefinition of MI Classification System, and the risk of cardiac death among 13,608 patients with acute coronary syndrome who were enrolled in the TRITON-TIMI 38 trial. The adjusted risk of cardiac death was evaluated by landmark analysis, starting at the time of the MI through 180 days after the event.

Results:

The risk of cardiac death at 6 months was higher in patients who had an MI compared with patients without an MI (6.5% vs. 1.3%; p < 0.001). This higher risk was present across all subtypes of MI including Type 4a (peri-percutaneous coronary intervention [PCI], 3.2%; p < 0.001) and Type 4b (stent thrombosis, 15.4%; p < 0.001). After adjusting for important clinical covariates, the occurrence of any MI was associated with a fivefold higher risk of death at 6 months (95% confidence interval [CI], 3.8-7.1) with increased risk across subtypes. The hazard of death was increased four times after Type 1 MI (spontaneous) (adjusted hazard ratio [HR], 4.1; 95% CI, 2.7-6.3; p < 0.001), threefold after Type 2 (demand related) (HR, 2.8; 95% CI, 0.9-8.8; p = 0.085), doubled in those with a Type 4a MI (peri-PCI) (HR, 2.4; 95% CI, 1.6-3.7; p < 0.001), and more than 10-fold (HR, 10.5; 95% CI, 1.18-93.6; p = 0.035) in those experiencing Type 5 MI (coronary artery bypass grafting related).

Conclusions:

The authors concluded that all types of MI are associated with a significantly increased risk of cardiovascular death on follow-up.

Perspective:

The change in the definition of MI to include the use of sensitive biomarkers had raised concerns about the clinical relevance of small elevation in biomarkers. This study demonstrates a clear adverse impact of all subtypes of MI on mortality, and supports the use of the universal definition for clinical as well as research purposes.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, ACS and Cardiac Biomarkers, Aortic Surgery, Interventions and ACS

Keywords: Myocardial Infarction, Acute Coronary Syndrome, Follow-Up Studies, Platelet Aggregation Inhibitors, Thiophenes, Piperazines, Risk Factors, Angioplasty, Balloon, Coronary, Stents, Percutaneous Coronary Intervention, Prognosis, Biological Markers, Thrombosis, Cardiovascular Diseases, Confidence Intervals, Coronary Artery Bypass, United States


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